Generally speaking, employers do not advertise for entry-level paralegal positions. This is because (when it comes to solicitors' firms anyway) employers receive a sufficient number of good-quality but unsolicited applications on a regular basis. Why pay a recruiter to find good people when good people are already approaching firms directly?
Some employers do advertise entry-level paralegal positions. Some of them do so because they don't receive the supply of unsolicited applications in the same way that solicitors' firms tend to do (e.g. in-house legal departments of less well-known companies). Others advertise because they have a corporate policy of advertising all vacancies in the organization (e.g. local authorities).
There are a great many legal recruiters: just Google that term to see! However the majority do not yet handle paralegal vacancies, although as the status of paralegals grows that is beginning to change quite quickly.
Since most legal recruitment companies primarily cater to solicitors' firms and big organisations such as banks, they tend to receive instructions only in respect of vacancies for experienced paralegals. Therefore do not be disappointed if you are rejected by recruitment consultants when you apply to be a registered candidate. Do try however!
Typically recruiters will retain people with more than one year's solid legal practice experience. Usually the only entry-level candidates they will accept are LPC/BPTC graduates who could not secure a solicitors' training contract/pupillage upon graduation. Even then they may also require at least six months paralegal experience.
It is important to flag that this prejudice is most acute in the big cities where there are big international/national/regional law firms. In other places - i.e. actually most of the country - both employers and recruiters may well be significantly more flexible.